On December 11, 1816, President James Madison signed the congressional act that formally admitted Indiana to the Union as the nineteenth state.

This encompassed an area northwest of a line beginning at the Ohio River, on the bank opposite the mouth of the Kentucky River, extending northeast to Fort Recovery in present-day western Ohio, and north to the border between the United States and Canada along a line approximately 84 degrees 45 minutes West longitude.

When the Indiana Territory entered the semi-legislative phase of government in 1805, the legislature gradually became the dominant branch, and the judges focused on judicial matters.

Governor Posey appointed Isaac Blackford, Jesse Lynch Holman, and Elijah Sparks as presiding judges over the circuit courts.

In the semi-legislative phase, the federal government paid the salaries of the territorial governor, judges, and secretary at a cost of approximately $6,687 per year.

These changes included reductions in some taxes, increases in others, and implementing licensing requirements for some types of business ventures in order to stabilize revenue.

[48][49] In 1803 Harrison and the general court judges passed legislation that evaded the Ordinance of 1787 in order permit slavery in the Indiana Territory through the use of indentured servitude laws.

Voters promptly rebuffed many of his plans for slavery, and in 1810 the territorial legislature repealed the indenturing laws that Harrison and the judicial court had enacted in 1803.

In addition, the Land Ordinance of 1785 called for the U.S. government to survey the newly acquired territory for future sale and development.

[59] Indiana, meaning "Land of the Indians", references the fact that most of the area north of the Ohio River was still inhabited by Native Americans.

[61][62] During the autumn of 1790, American forces under the command of General Josiah Harmar unsuccessfully pursued the Miami tribe near present-day Fort Wayne, Indiana, but had to retreat.

In the meantime, Major Jean François Hamtramck led an expedition from Fort Knox to Wea, Potawatomi, and Kickapoo villages on the Wabash, Vermilion, and Eel Rivers, but his company lacked sufficient provisions to continue, forcing a return to Vincennes.

[63][64] In 1791 Major General Arthur St. Clair, the governor of the Northwest Territory, commanded about 2,700 men in a campaign to establish a chain of forts and enforce peace in the area.

[65][66] In August 1794, General "Mad Anthony" Wayne organized the Legion of the United States and defeated a Native American force at the Battle of Fallen Timbers.

As a result of the treaty, the Miamis considered themselves allies with the United States, and thousands of acres of newly ceded western lands attracted an increasing number of new settlers to what would become the Indiana Territory.

In 1803 President Thomas Jefferson granted Harrison the authority to negotiate and conclude treaties with the Native American tribes in the territory.

Harrison oversaw the establishment of thirteen treaties that ceded more than 60,000,000 acres (24,000,000 hectares) of land from Native American tribes, including most present-day southern Indiana, to the U.S.

After the signing of the contentious and disputed Treaty of Fort Wayne (1809), in which Harrison acquired for the U.S. government more than 250,000,000 acres (100,000,000 hectares) of land in what later became central Indiana and eastern Illinois, tensions between the Native American and settlers on the frontier neared the breaking the point.

[81][82] The availability of low-cost federal land led to a rapid increase in the population of the territory, with thousands of new settlers entering the region every year.

From October 1, 1804, until July 4, 1805, administrative powers of the District of Louisiana were extended to the governor and judges of the Indiana Territory as a temporary measure to establish a civil government for the newly purchased lands.

[86] One of the most notable events during the Indiana Territory's administration of the District of Louisiana was the Treaty of St. Louis in which the Sac and Fox tribes ceded northeastern Missouri, northern Illinois, and southern Wisconsin to the United States.

[89] In 1810 Tecumseh and an estimated 400 armed warriors traveled to Vincennes, where he confronted Harrison and demanded that the governor rescind the Treaty of Fort Wayne.

Afterwards, Tecumseh journeyed south to meet with representatives of the tribes in the region, hoping to create a confederation of warriors to battle the Americans.

Harrison was publicly hailed as a national hero and the nickname of "Old Tippecanoe," despite the fact that his troops had greatly outnumbered the Indian forces and had suffered many more casualties.

[93] On December 5, 1804, Governor Harrison issued a proclamation announcing the Indiana Territory's advancement to the semi-legislative phase of government.

The first legislative session of the territorial general assembly met in Vincennes from July 29 through August 16, 1805, and chose Benjamin Parke as its first delegate to the U.S. House of Representatives.

Tecumseh's followers who remained behind continued to raid the countryside and engaged in the Siege of Fort Harrison, which was the U.S. Army's first land victory during the war.

The Treaty of Ghent (1814) ended the war and relieved American settlers from their fears of attack by the nearby British and their Indian allies.

[103] Efforts to attain statehood for Indiana were revived in 1815,[104] following a census made in 1814–15 that found the territory's total population had reached 63,897.

Territorial legislature presented another petition to the U.S. House on December 28, 1815, and the U.S. Senate on January 2, 1816, prompting Jennings to introduce a bill to authorize the election of delegates to a constitutional convention to discuss statehood for Indiana.